The proposed work is designed to determine whether or not differences can be found in deoxynucleotide polymerizing enzymes from normal and leukemic human cells and whether or not polynucleotides and some streptovaricin derivatives would selectively inhibit those deoxynucleotide polymerizing enzymes from leukemic cells which may be quantitatively different, altered or unique to leukemic cells. It is hoped that selective inhibitors of leukemic cell enzymes may be useful in the chemotherapy of leukemia. BIBLIOGRAPHIC REFERENCES: Srivastava, B.I.S., Minowada, J., and Moore, G.E., High Terminal Deoxynucleotidyl Transferase Activity in a T-Cell Line (RPMI 8402) Derived from Peripheral Blood of a Patient with Acute Lymphoblastic Leukemia. J. Natl. Cancer Institute. 55: 11-14, 1975. Srivastava, B.I.S. , Terminal Deoxynucleotidyl Transferase Activity in T- and B-Cells. Fed. Proc. 34:494, 1975.